In silico prediction of potential regulatory regions affected by thec.1-171 C>G, described previously by our group in a patient with mild antithrombin deficiency [12] identified potential binding sites for hepatocyte nuclear factor alpha (HNFα) thyroid receptor alpha (TRα), chicken ovalbumin upstream promoter-transcription factor I (COUP-TFI), and retinoid X receptor alpha/vitamin D receptor (RXRα/VDR). Here, RXRA is linked to hereditary antithrombin deficiency.